When If App.PrevInstance doesn't detect a previous instance

Quote:

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Originally posted by hspc
anyway this is my solution for this prolem :
[....]

How does it work ?
it creates a mutex (shared object that hace a uniqe name)..
if you try to recreate it you get the error :
ERROR_ALREADY_EXISTS
this is the whole idea...

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I like your solution.

Another way (not this good, however)
is to have a check in sub main for a particular form
(FindWindow api will find it even if it is not visible)
you load and do not show. If you find it, program is
already running, if not, it is first instance
ie attached code

But your solution is better...
:)

Cimperiali..
thank you for the nice comment :)

If anyone is interested, here is my solution to PreviousInstance : DDE or LinkItem as VB call it.

On the main form, have these properties set :
LinkMode : 1 - Source
LinkTopic : "AppLinkTopic" [Can be anything]

Then on my Form Load using an invisible textbox I named TxtDDE :

Code:

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TxtDDE.LinkMode = 0 ' None
TxtDDE.LinkTopic = "YourApplicationTitleHere|AppLinkTopic"
On Error goto NoDDE
TxtDDE.LinkMode = 2 ' Manual - Link to existing dde host
TxtDDE.LinkExecute "SHOWUP" ' When host receive this, it should activate itself
Unload Me
End

NoDDE:
' Continu loading here.

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Here is the code I use to deal with the SHOWUP command (on the main form) :

Code:

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Private Sub Form_LinkExecute(CmdStr As String, Cancel As Integer)
  If (UCase(CmdStr) = "SHOWUP") Then
    FrmMain.Visible = True
    FrmMain.WindowState = vbNormal
    FrmMain.SetFocus
  End If
  ' I use the same method to notify my application to quit ( for updates )
  If (UCase(CmdStr) = "QUIT") Then FrmLoad.Menu_TrayQuit_Click
End Sub

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this works for me but only shows a message:

If App.PrevInstance Then
MsgBox "Application is already running"

n i need to load the previnstance, here's the code for getting the program to the taskbar:

Private Sub Form_Resize()

If Me.WindowState = 1 Then
'The user has minimized his window

Call Shell_NotifyIcon(NIM_ADD, IconData)

' Add the form's icon to the tray

Me.Hide

' Hide the button at the taskbar

End If

End Sub

Private Sub Form_Load()

With IconData

.cbSize = Len(IconData)
' The length of the NOTIFYICONDATA type

.hIcon = Me.Icon
' A reference to the form's icon

.hwnd = Me.hwnd
' hWnd of the form

.szTip = "Cyber-Net Lite" & Chr(0)
' Tooltip string delimited with a null character

.uCallbackMessage = WM_MOUSEMOVE
' The icon we're placing will send messages to the MouseMove event

.uFlags = NIF_ICON Or NIF_TIP Or NIF_MESSAGE
' It will have message handling and a tooltip

.uID = vbNull
' uID is not used by VB, so it's set to a Null value

End With

End Sub

Private Sub mnuExit_Click()

Unload Me
' Unload the form

End
' Just to be sure the program has ended

End Sub

Private Sub mnuShow_Click()

Me.WindowState = vbNormal
Shell_NotifyIcon NIM_DELETE, IconData
Me.Show

End Sub
Private Sub Form_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)

Dim msg As Long

msg = X
' The message is passed to the X value

' You must set your form's ScaleMode property to pixels in order to get the correct message

If msg = WM_LBUTTONDBLCLK Then
' The user has double-clicked your icon

Call mnuShow_Click
' Show the window

ElseIf msg = WM_RBUTTONDOWN Then
' Right-click

PopupMenu mnuPopup
' Popup the menu

End If

End Sub

Private Sub Form_Unload(Cancel As Integer)
Shell_NotifyIcon NIM_DELETE, IconData
Cancel = -1
End Sub

Can anybody please help me?

thnx